<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      var a = prompt('请输入用户名');
      var b = prompt('请输入密码');
      while (a !== 'admin' || b !== '123456') {
        a = prompt('请输入用户名');
        b = prompt('请输入密码');
      }
      alert('登录成功');
    </script>
  </body>
</html>
